package cn.ddy.utils;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import java.io.IOException;
import java.io.Reader;

public class MyBatisUtil {
    //将SqlSession放入到ThreadLocal中，实现与当前线程绑定
    private static ThreadLocal<SqlSession> threadLocal = new ThreadLocal<>();
    private static SqlSessionFactory factory = null;

    static {
        try {
            Reader reader = Resources.getResourceAsReader("mybatis-config.xml");
            factory = new SqlSessionFactoryBuilder().build(reader);
        } catch (IOException e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }
    }

    private MyBatisUtil() {
    }

    //获取跟当前线程绑定的SqlSession对象
    public static SqlSession getSqlSession() {
        SqlSession sqlSession = threadLocal.get();
        //如果ThreadLocal中没有，通过SQLSessionFactory创建一个
        if (sqlSession == null) {
            sqlSession = factory.openSession();
            //放入到ThreadLocal中
            threadLocal.set(sqlSession);
        }
        return sqlSession;
    }

    //关闭SqlSession对象
    public static void closeSqlSession() {
        //先从ThreadLocal中取
        SqlSession sqlSession = threadLocal.get();
        //若SqlSession不为null，关闭，并从ThreadLocal中移除
        if (sqlSession != null) {
            sqlSession.close();
            threadLocal.remove();
        }
    }
}